In three test tubes A, B and C, three different liquids namely, distilled water, underground water and distilled water in which a pinch of Calcium sulphate is dissolved, respectively are taken. An equal amount of soap solution is added to each test tube and the contents are shaken. In which test tube will the length of the foam (lather) be longest? Justify your answer.
Soap lather:-
Therefore, the length of the foam will be the longest in test tube A, which consists only of distilled water because lather is formed easily in the soft water and distilled water is soft water.